Automatic toaster



Filed Sept. 19, 1932 4 Sheets-Sheet 2 INVENTOR Mumcz H. GRAHAM ATTORNEYS y 1936- v M. H. GRAHAM 2,039,956

AUTOMATIC TOASTER Filed Sept. 19, 1932 4 Sheets-Sheet 3 I-vc--ron MAURICE H. GRAHAM y 5,1936. M. H. GRAHAM 2,039,956

' AUTOMATIC TOASTER Filed Sept. 19, 1932 V 4 Sheets-Sheet 4 f 9- INVENTOH MAURICE H. GRAHAM 244 ewflll -r ATTORNEYS Patented May 5, 1936' UNITED STATES PATENT OFF-ICE 2,039,956 r V e H AUTOMATIC TOASTER Maurice n. Graham, St. mun Park, Minn. Application September 19, 1932, Serial No. 663,765

13 Claims. (01. 219-19) This invention concerns itself with toasters and more particularly with bread toasters which are automatically operative to control the toasting operation. Various types of automatic toasters have heretofore been proposed and among these types may be mentioned that provided with a clock mechanism with manual means only for regulating the same, and the types involvingv use of surface temperature of the bread, its moisture content and its interior temperature. Another type of automatic toaster is one wherein a clock or other timing mechanism is automatically controlled or regulated by means of a thermally responsive device. The present invention relates more specifically to the latter type of automatic toaster.

Previous toasters of this type have embodied the use of thermally responsive devices which are subject to the heat of the oven in which the toast- 0 ing operation is carried out, but a toaster constructed in accordance with the present invention includes a thermally responsive member which is not directly subject tooven heat but which is aifected by the heat of a separate heating device which is operated with the heating device within the toasting chamber or oven of the toaster. Preferably, the main heating element of the toaster is electrical and the supplemental heating element for the thermally responsive device is also elec-,

trical and connected in circuit with the main heating element, thereby to be turned on and oil with the main heating element and to simulate the conditions of heat developed in the toasting chamber by the main heating element.

In a toaster so constructed that the thermostat is directly subjected to oven heat it is difllcult to produce a design which will eliminate possibility of the thermostat or its associated mechanism becoming clogged or incrusted with-bread particles. By providing a separate heating element which operates with the heating element in the oven and which produces convection currents separate from any which may be created by the oven,

it is a simple matter to remove the thermally responsive mechanism from a position in which it might become clogged with bread particles, and it is furthermore simple to operate successfully with a toaster which is so designed as to shield the oven from draft or convection influences between 0 and/or during toasting operations.

The various aspects of the invention will be more clear upon the consideration of an embodiment of the invention which will be described in the specification and drawings, but it will of course application of the principles underlying the invention.

Referring more particularly to the drawings,

Figure 1 is a front view of the toaster, the casing being broken away in order to more clearly disclose the mechanism therein;

Figure 2 is a cross-section along the line 2-2 of Figure 1;

Figure 3 is a cross-section along the line 33 of Figure 2;

. Figure 4 is a bottom plan view of the toaster;

Figure 5 is a fragmentary view showing the 'mechanism for adjusting the variable speed clock by means of the thermally responsive device;

Figure 6 is a cross-section along the line 6-6 of Figure 5;

Figure '7 is a cross-section along the line 1-1 of Figure 1 and is a view of the timing mechanism; and,

Figure 8 is a wiring diagram showing the manner in which the heating elements are connected.

In the drawings, there is shown an automatic toaster having a base member 4 formed, of stamped sheet metal or the like and having an outer casing 6 which is also formed of stamped sheet metal. Within the casing 6 there is arranged a pair of heating elements.8 and 9 be-- tween which bread slices to be toasted are moved upon the bread carrier Ill.- The heating elements are disposed within a toasting chamber or oven formed by the sheet metal end walls [2 and M and by the sheet metal side walls I6 and I8.

A handle 2|! extends outside of the casing 6 and has mechanism associated therewith for winding a timing mechanism shown more particularly in Figures 1, 2, 5, 6 and '7, for depressing the bread carrier Ill and for closing an electrical switch 22. The specific structure will not be described since it forms no part of the present invention and is fully described in two pending applications of Murray Ireland, the first of which is entitled Toasters, Serial Number 437,071, and

was filed March 19, 1930; and the second of which is entitled Timing mechanismZSerial Number 457,893, and which was filed on May 31, 1930.

stitutes a variable speed clock and is of the same K type as thatapplied to the present toaster.

5 be understood that this merely represents one In the operation of the toaster, a bread slice is 'placed upon the carrier I II while it is in upperposition and the bread is moved completely into the oven between the heating elements. In the i course of the downward movement of'the handle, a main switch 22 for the heating elements is automatically closed, and when the carrier reaches lowermost position it is held therein by a catch member later released by the timing mechanism. Upon release of the catch member the bread'carrier is moved back into uppermost position by fixed on the slide 28 to which the handle 28 is attached. When the handle is depressed, the

lower surface of the member 25, which is prefere ably V-shaped, engages the stud or pin and pulls down the rack 28, thereby rotating the spring shaft 28 and energizing the spring 30 of the timing mechanism. As the spring unwinds it raises the rack 24, thereby also raising the slide 25' and member 25. The latter is provided with an upper cam surface which engages a catch for holding the bread carrier in lowermost position and operated to release the bread carrier so that it may move to uppermost position after a predetermined amount of travel on the part of rack 24. By varying the speed with which the spring unwinds and the clock mechanism raises the rack 24, the time durof a spring 44.

' side of this wall.

ing which the bread carrier'is held in lowermostposition and the bread slices consequently heldin 'the oven may thus be governed.

As the spring 38 unwinds, it rotates a shaft 32 having a cam 34 fixed thereon, by means of a gear train generally designated at 36. The cam 84 operates within the forked end of an oscillator 48 which is pivotally mounted on a pin 4| and has one end attached to a balance wheel 42, by means By varying the position of the pivoted oscillator 48 with respect to the cam 34 and balance wheel 42, the speed of the timing mechanism may be varied. The foregoing structure is all fully described in the Ireland applications above referred to, and therefore need not be described with further particularity. It is suflicient to note'that a variation of the position of the pin 4| upon which the oscillator 48 is mounted results in a variation of the time during which the bread carrier I8 holds a bread slice within the oven, and during which the heating elements are energized. q

At one end of the sheet metal wall |8 of the toasting chamber, there is provided an elongated tubular chamber 50, substantially rectangular in cross-section, which is formed of side walls 52 and 54 and end walls 56 and 58. The casing 58 is located inside of the outer casing 8 of the toaster andits wall 54 comprises'substantiallya continuation of the wall I8, although it will of course be understood that if desired the wall '|8 may be continuous and the casing 58 may be located out- Secured to the wall 58 of the chamber 50 there is a mounting 58 for a thermostatic member 68 which is adapted to warp into the dotted line position'shown in Figure -2 upon being heated. The wall 58 has mounted thereon a heating element 52 which is suitably insulated and the heating element 82 supplies the heat controlling the movement of the thermostat 88, it

being noted that the thermostat is directly subject aosacte to the radiant heat of the element. As shown in Figure 8, the heater 82 is connected in circuit with the toast heating elements 8 and 8 and all of these heaters are controlled by the main switch 22.

The thermostat 68' has a lost motion connection with the hooked end of a lever 54 which has its other end connected to one arm of a bell crank lever 56. The other arm of this bell crank lever is connected to a link 68 which in turn is connected to the free end of a lever pivoted at 12. Lever 18 carries the pin 4| upon which the oscillator 48 is pivoted. Upon'a heating of the thermostat 58. it will moveto the right, as shown in Figure 1, and cause a rotation of lever 10, with the result that the position of the oscillator 48 in respect to the cam 34 will be varied and the speed of the timing mechanism will accordingly be varied. As shown in Figure 2, wherein the thermostat is shown in full lines in the position it occupies when at room temperature, the thermostat mustmove some distance before it takes up the lost motion in its connection to the lever 84 and begins regulating the speed of the clock mechanism. This is to insure that the toaster will operate at slow speed while cold. After being heated, the thermostat '60 operates to increase the speed of the timing mechanism and thereby shortens the peri od during which bread is held within the oven. It will be understood that the lost motion connection may be dispensed with or varied at will in accordance with the various features of design. The speed of the clock may also be controlled manually. The knob 14 extends outside of the casing 8 and is fixed on a shaft 18, also carrying a gear wheel 18, which meshes with a rack 88 fixed to the member 82 to which the lever I8 is pivoted.

. and the handle 28 is thereupon depressedwith the result that the bread carrier will move down to carry the bread into the oven, the spring of the timing mechanism will be wound, and the main switch 22 of both the toast heating elements 8 and 9 and the heater 52 in the chamber 58 will be closed. As current begins to flow, the toast heating elements 8 and 9 will begin to heat up and the heating elements 52 will likewise become heated, with the result that the'bi-metal thermostatic member 88 will warp and operate to increase the speed of the timing mechanism. When the timing mechanism has raised rack 24 a predetermined amount, the bread carrier will be released and moved to uppermost position, and the main switch will automatically open.

If the toaster is not allowed to cool completely before a second slice of bread is inserted, the

heating element 82 and chamber 58 will also not 7 have cooled completely, with the result that thermostat 68 will still retain some heat. Therefore, the member 60 will increase the average speed of the timing mechanism and the timing period for the second slice will be less than the period of the first slice and with succeeding slices the timing period will depend upon the initial temperature of the thermostat 58 which is dependent upon oven conditions.

The parts are so designed that the temperature of thermostat 58 will increase proportionately with oven temperature. Lighter or darker toast may be produced by manipulation of knob 14 and once this knob is set at the desired point, completely uniform toast will result irrespective of starting oven temperature or periods of waiting between the toasting of successive slices. The temperature of thermostat 60 will also decrease proportionately with oven temperature because of the fact that it is subjected to the natural draft set up through the open bottom of. the

' chamber 50 andpassing out of'its open top upon claim as new and desire to secure by Letters Patent of the United States is as follows:

-1. In an automatic toaster having a toasting chamber, toast heating means within said chamber, and means for supporting a bread slice in position to be toasted by said toast heating means, a heater operated simultaneously with said toast heating means and positioned outside of said toasting chamber, said heater being mounted and positioned so as to set up an air draft when heated, a thermally responsive device subject to the heat from said heater and located in the draft created thereby, and means associated with said thermally responsive device for terminating the toasting of the bread slice.

2. In an automatic toaster having toast heating means, and means for supporting a bread slice in position to be toasted by said toast heating means, a heater operated concurrently with said toast heating means, a chamber for said heater having an opening therein through which an air draft is set up upon operation of the heater, a thermally responsive device within said chamber and subject to the heat from said heatwith, a chamber for said heater having an opening therein through which an air draft is set up upon operation of the heater, a thermally responsive device subject to the heat from the heater and positioned in the draft created thereby, and means associated with said thermally responsive device for terminating the toasting of the bread slice.

4. An automatic toaster comprising a toasting chamber, toast heating means within said toasting'chamber, means for supporting a bread slice in said toasting chamber in position,to be toasted by said toast heating means, alieater removed from and operated concurrently with said toast heating means, a; chamber for said heater having an opening through which a draft is set up upon operation of the heater, a thermally responsive device in said heater chamber subject to the heat from the heater and positioned in the draft created thereby, and means associated with said thermally responsive device for terminating the toasting of the bread slice.

5. An automatic toaster comprising a toasting chamber, electrical toast heating means within said chamber, means for supporting a bread slice 5 within said chamber in position to be toasted by said heating means, an electrical heater in circuit with said toast heating means'and operated simultaneously therewith, a chamber for said heating means and having an opening through which a draft is set up upon operation ofthe heating means, a thermally responsive device subject to the heat from the heater andal'so p0.- sitioned in the draft created thereby, and. means associated with said thermally responsive device for terminating the toasting of the bread slice.

6. An automatic toaster comprising a toasting I chamber, electrical toast heatingmeans within said chamber, means for supporting a bread slice in position to betoasted by said heating means, 20 an electrical heater in circuit with said toast heating means and operated simultaneously 'therewith,said heater being located outside of said toasting chamber and being arranged to produce a draft upon being heated, a thermally 25 responsive device exposed to the radiant heat of said heater and located in the path of the draft created thereby, means including a timing mechanism for terminating the toasting of bread slices, and means associated with said thermally responsive device for controlling the operation of said timing mechanism.

7. An automatic toaster comprising a toasting chamber, electrically operated toast heating means within said chamber, means for supporting a bread slice in position to be toasted by said heating means, an electrical heater in circuit with said toast heating means and adapted to be operated simultaneously therewith, a chain her for said heater having an opening therein through which a draft is set up upon operation of the heater, said heater chamber being located outside of said toasting chamber, a thermally responsivedevice located within said heater cham- 1 when heated, a thermally responsive device exposed to the heat of the heater and located in the path of the draft created thereby, and means associated with said thermally responsivedevice for controlling said means for removing the bread slices from the oven.

9. An automatic toaster comprising toast heating means, means for moving a bread slice into and away from position to be toasted by said heating means, a variable speed clock controlling said moving means, a heater operated concurrently with said toast heating means, and -a thermally responsive device exposed to heat given of! by 7 said heater and also exposed in the draft created thereby, said thermally responsive device being operatively connected to said variable speed clock to regulate the same.

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